The management of post-herpetic neuralgia

Real-world effectiveness of recombinant zoster vaccine in self-identified Chinese individuals aged ≥50 years in the United States

We evaluated the vaccine effectiveness (VE) of two doses of recombinant zoster vaccine (RZV) against herpes zoster (HZ) and postherpetic neuralgia (PHN) in Chinese adults at Kaiser Permanente Southern California (KPSC). Chinese KPSC members were identified based on self-reported ethnicity or self-reported preferred spoken/written language. Those aged ≥50 years who received two doses of RZV 4 weeks to ≤ 6 months apart were matched 1:4 to RZV unvaccinated Chinese members and followed through June 2022; second doses were accrued 6/1/2018-12/31/2020. We estimated incidence and adjusted hazard ratios (aHRs) with 95% confidence intervals (CIs) comparing outcomes (HZ and PHN). Adjusted VE (%) was calculated as (1-aHR)×100. 3978 RZV vaccinated Chinese members were matched to 15,912 RZV unvaccinated Chinese members. The incidence per 1000 person-years (95% CI) of HZ in the vaccinated group was 1.5 (0.9-2.5) and 10.9 (9.8-12.1) in the unvaccinated group; aHR (95% CI) was 0.12 (0.07-0.21). Adjusted VE (95% CI) was 87.6% (78.9-92.7) against HZ. We identified 0 PHN cases in the vaccinated group and 19 in the unvaccinated group. Among Chinese adults aged ≥50 years, two doses of RZV provided substantial protection against HZ and PHN supporting the real-world effectiveness of the vaccine in this population.

Association between Glycosylated Hemoglobin Levels and Vaccine Preventable Diseases: A Systematic Review

People with diabetes are at higher risk of serious complications from many vaccine-preventable diseases (VPDs). Some studies have highlighted the potential impact of glycosylated hemoglobin levels (HbA1c), but no systematic review has synthesized these findings. Of the 823 identified studies, 3 were included, for a total of 705,349 participants. Regarding the incidence of herpes zoster (HZ), one study found that higher HbA1c levels at the baseline (>10.3%) were associated with a significantly higher risk of HZ of 44%, compared to those with a good HbA1c control (6.7%). On the contrary, the second one reported that when compared to the reference group (HbA1c of 5.0-6.4%), participants with a HbA1c less than 5.0% were at higher risk of HZ of 63%, whilst participants with a HBA1c more than 9.5% had a similar risk. Finally, the third study observed that diabetes, defined using a value of HbA1c more than 7.5%, was associated with an increased risk of mortality in men with COVID-19. In conclusion, both high and low HBA1c levels appear to be associated with a higher risk of HZ. Regarding COVID-19, a value of HbA1c more than 7.5% was associated with a higher risk of death in COVID-19, but only in men.

Efficacy of repetitive paravertebral block combined with medication in the treatment of zoster-related pain with different courses

Objectives:

To compare the clinical outcomes of repetitive paravertebral block (PVB) combining oral medication in the treatment of zoster-related pain (ZP) with different courses.

Methods:

Sixty-seven patients with ZP were divided into 3 groups based on their course of herpes zoster (HZ). Group I: 24 patients with acute herpetic neuralgia (within one month of disease onset); group II: 22 patients with subacute herpetic neuralgia (disease onset from 1 to 3 months); group III: 21 patients with postherpetic neuralgia (more than 3 months since disease onset). All patients received ultrasound-guided repetitive PVB with oral gabapentin and tramadol sustained-release tablets. The VAS and QS scores and the incidences of hematoma, dizziness, nausea, and drowsiness were compared at 1 day, 3 months, and 6 months after treatment.

Results:

Pain intensity and sleep quality of the 3 groups improved to varying degrees after treatment. The best efficacy was achieved in the acute group, followed by the subacute group, and the poorest efficacy was observed in the chronic group.

Conclusion:

The efficacy of ultrasound-guided repetitive PVB with oral medication varied with the courses of HZ. The shorter the time since onset, the better the efficacy. This combined treatment showed better efficacy in patients at the acute and subacute stages and significantly improved their pain and sleep quality, while demonstrating limited pain relief in chronic patients.

Zoster Vaccination in Older Adults: Efficacy and Public Health Implications

Shingles and its most common disabling complication, post-herpetic neuralgia, represent a serious public health challenge in the older population. The decline in the T-cell-mediated immune response to varicella zoster virus after age 50 is clearly associated with increased risk of viral reactivation, causing an acutely painful zoster rash, which may have a severe prodrome of dermatomal pain and persist as seriously debilitating post-herpetic neuralgia well beyond the resolution of the rash. However, new vaccines and adjuvants are being developed and trialed and are now more effective in preventing shingles and the sequelae of post-herpetic neuralgia. Those vaccines that possess the ability to enhance antigen presentation and reverse memory T-cell exhaustion, as well as diminish the immune suppressive effects of regulatory T cells, are most likely to be effective in older adults.

Comparison of ropivacaine with ropivacaine and fentanyl in continuous epidural analgesia for postherpetic neuralgia: A STROBE-compliant retrospective study

Continuous epidural analgesia (CEA) using local anesthetics is frequently used to control herpes zoster pain and prevent postherpetic neuralgia (PHN). However, few studies have been conducted to determine the efficacy of epidural drugs administered as CEA to manage PHN. This retrospective study was designed to evaluate the effectiveness of CEA with ropivacaine alone or with ropivacaine and fentanyl for controlling pain caused by PHN.We reviewed the medical records of 71 patients. We studied 2 groups: epidural ropivacaine (ER; CEA with ropivacaine alone; n = 44) and epidural ropivacaine and fentanyl (Epidural ropivacaine and fentanyl (ERF); CEA with ropivacaine and fentanyl; n = 27). To evaluate pain, a numeric rating scale (NRS) was evaluated at 6 time points: immediately before the procedure (baseline NRS score); 1 hour after the procedure; 14 days after the procedure; and 1, 3, and 6 months after the procedure. Complication rates were recorded during CEA. We also investigated whether additional invasive procedures were needed due to insufficient pain control during the 6-month follow-up period.After adjusting for confounding variables, there were no significant differences in the NRS scores between the 2 groups at any time point. The adjusted odds ratio for additional invasive procedures within 6 months after CEA was 1.03-times higher in the ERF group than in the ER group, but this difference was not statistically significant (95% confidence interval: 0.33-3.23, P = .96). Rates of complication (dysuria, vomiting, nausea, itching sensation, and hypotension) during CEA were higher in the ERF group than in the ER group. However, the differences were not statistically significant.There was no difference in the management of pain in patients with PHN between the groups. Epidural administration of fentanyl with ropivacaine did not improve pain management when compared to ropivacaine alone. Although not statistically significant, the incidence of complications during CEA was higher in the opioid combination group.

Comparison of the Analgesic Effect of Ropivacaine with Fentanyl and Ropivacaine Alone in Continuous Epidural Infusion for Acute Herpes Zoster Management: A Retrospective Study

Background and Objectives: Currently, few studies have reported the effects of opioids during continuous epidural infusion (CEI) to control pain owing to herpes zoster (HZ). This study aimed to retrospectively compare the effectiveness of epidural opioids in the treatment of acute HZ pain. Materials and Methods: We reviewed medical records of 105 patients who were divided into two groups: R group (CEI with ropivacaine) and RF group (CEI with ropivacaine and fentanyl). Clinical efficacy was evaluated using the numeric rating scale (NRS) score for 6 months after the procedures. We compared the percentage of patients with complete remission in each group. We investigated the complication rates during CEI. Results: No significant differences in the NRS scores were observed between the two groups in the 6-month period. The adjusted odds ratio (OR) for patients included in the complete remission was 0.6 times lower in the RF group than in the R group (95% confidence interval: 0.22–1.71, p = 0.35). The OR for complications during CEI was higher in the RF group than in the R group. However, the difference was not statistically significant. Conclusions: No difference was observed in the management of HZ pain and the prevention of postherpetic neuralgia between the two groups. The incidence of complications tended to be higher in the RF group than in the R group.

The Impact of Reactogenicity After the First Dose of Recombinant Zoster Vaccine on the Physical Functioning and Quality of Life of Older Adults: An Open-Label, Phase III Trial

BACKGROUND

Herpes zoster and its related complications are associated with significant medical burden, which negatively affects quality of life and daily functioning of the patients. The recently licensed recombinant zoster vaccine (RZV) offers high efficacy but is associated with local and systemic reactions. This study assessed the impact of RZV on the quality of life and daily functioning of participants and implications for caregivers.

METHODS

Four hundred and one adults aged 50 years or older received single RZV doses at 0 and 2 months in this open-label, single-arm, multicenter study (NCT02979639). Change in mean SF-36 Physical Functioning score following first-dose administration, quality of life, reactogenicity, safety, productivity loss, and health care resource utilization was assessed. The current analysis was performed post-vaccine dose-1; safety follow-up will continue until 1 year post-dose-2.

RESULTS

The most common solicited local symptoms were injection-site pain (77.5%), redness (23.0%), and swelling (13.3%); the most frequent solicited systemic reactions were fatigue (33.5%), headache (28.3%), and myalgia (26.8%). Grade 3 reactogenicity occurred in 9.5% of participants and was associated with a transient clinically important decrease in SF-36 Physical Functioning score (affecting activities such as walking, carrying groceries, climbing stairs) on Days 1 and 2 post-first vaccination. No clinically meaningful reductions in mean SF-36 Physical Functioning scale scores from pre- to post-RZV dose-1 were observed (mean +1.9 points, primary end point), and no overall quality-adjusted-life-year loss was recorded post-dose-1. Five participants reported lost workdays; caregiver workload was not increased.

CONCLUSIONS

Overall, the physical functioning and quality of life of older adults were not affected by a first RZV dose. The observed reactogenicity was consistent with previous studies.

Immunosenescence Modulation by Vaccination

A decline in immune function is a hallmark of aging that leads to complicated illness from a variety of infectious diseases, cancer and other immune-mediated disorders, and may limit the ability to appropriately respond to vaccination. How vaccines might alter the senescent immune response and what are the immune correlates of protection will be addressed from the perspective of (1) stimulating a previously primed response as in the case of vaccines for seasonal influenza and herpes zoster, (2) priming the response to novel antigens such as pandemic influenza or West Nile virus, (3) vaccination against bacterial pathogens such as pneumococcus and pertussis, (4) vaccines against bacterial toxins such as tetanus and Clostridium difficile, and (5) vaccine approaches to mitigate effects of cytomegalovirus on immune senescence. New or improved vaccines developed over recent years demonstrate the considerable opportunity to improve current vaccines and develop new vaccines as a preventive approach to a variety of diseases in older adults. Strategies for selecting appropriate immunologic targets for new vaccine development and evaluating how vaccines may alter the senescent immune response in terms of potential benefits and risks in the preclinical and clinical trial phases of vaccine development will be discussed.

Acupuncture for Central Pain Affecting the Ribcage following Traumatic Brain Injury and Rib Fractures – a Case Report

This case report describes the use of acupuncture in the management of chronic central pain in a 51 year old man following severe traumatic brain injury and multiple injuries including rib fractures. The patient reported rapid and significant improvements in pain and mood during a course of acupuncture treatment. Chronic pain following traumatic brain injury is a significant problem. Chronic pain after rib fractures is also commonly reported. Acupuncture is widely used in the management of pain but its use has been reported rarely in the traumatic brain injury literature. This case report suggests that acupuncture may be a useful option to consider in these patients. Outcome was assessed formally using a 0 10 verbal numerical rating scale for pain, and the Hospital Anxiety and Depression Scale (HADS) for psychological status before and after the course of treatment. These scales are widely used in clinical practice as well as in research involving patients with traumatic brain injury, although they have not been validated in this population. The changes in this patient's outcome scores were not consistent with the benefits he reported. Treatment of this patient highlighted the difficulties of using standardised self rating scales for patients with cognitive impairment. The report also discusses the effects of acupuncture on this patient's mood.

The effect and safety of ozone autohemotherapy combined with pharmacological therapy in postherpetic neuralgia

Introduction

We investigated the effect and safety of ozone autohemotherapy combined with pharmacological therapy in postherpetic neuralgia (PHN).

Methods

Ninety-eight patients with PHN were enrolled in this study and randomly divided into a pharmacological therapy group and ozone autohemotherapy group (49 patients in each group). The PHN patients in the pharmacological therapy group were administered pharmacological therapy for 2 weeks, whereas PHN patients in the ozone autohemotherapy group were given ozone autohemotherapy (200 mL blood from patients, the concentration of medical ozone was set as 30 μg/mL using an ozone medical apparatus, 40 mL medical ozone was incubated in 200 mL autologous blood for 3–5 minutes) combined with pharmacological therapy for 2 weeks. The Visual Analog Scale (VAS), the 50% VAS reduction in the initial value, McGill Pain Questionnaire (MPQ), the Patients’ Global Impression of Change (PGIC) scale, and the World Health Organization Quality of Life (WHOQOL-BREF) instrument were used to evaluate the outcomes of all PHN patients before therapy and at 1 week, 1 month, and 3 months after therapy.

Results

Forty-five patients in the pharmacological therapy group and 47 patients in the ozone autohemotherapy group completed the study. Compared with before therapy, the two groups showed significant improvements in VAS, MPQ, PGIC, and WHOQOL-BREF scores after therapy (P<0.05). Moreover, compared with the scores of the pharmacological therapy group, the ozone autohemotherapy group’s scores were significantly improved in the VAS, MPQ, PGIC, and WHOQOL-BREF as well as the 50% VAS reduction of the initial value after therapy (P<0.05). Finally, there were no statistically significant differences in adverse effects between groups after therapy (P>0.05).

Conclusion

The results of this study demonstrated that ozone autohemotherapy combined with pharmacological therapy was superior to isolated pharmacological therapy in patients with PHN and was an effective and safe way to relieve PHN.

Effectiveness of continuous epidural analgesia on acute herpes zoster and postherpetic neuralgia: A retrospective study

Despite early treatment of herpes zoster (HZ), postherpetic neuralgia (PHN) can persist. This study was designed to compare the therapeutic and pain relief effects of continuous epidural analgesia (CEA) on the chronic phase as well as the acute phase of HZ with standard medical treatment.Medical records of 227 patients with moderate to severe zoster-associated pain that had not responded to standard medications were retrospectively reviewed. Patients received standard treatment alone (medical group) or standard treatment plus concurrent CEA (epidural group). The acute and chronic groups were classified according to a 4-week cut-off with regard to time between the onset of the rash and the first treatment. Four groups were studied: Group A (acute/medical group); Group B (acute/epidural group); Group C (chronic/medical group); and Group D (chronic/epidural group). Pain was assessed using the visual analog scale (VAS) and measured every 2 weeks for 6 months. We compared the pain rating at 6 months after the first treatment with the initial pain rating. Response to treatment was defined as a ≥50% reduction in pain severity since the initial visit. Remission was considered complete for patients whose VAS pain score was ≤2 for >3 successive visits and who no longer needed medical support.Patients who received a combination of standard treatment plus CEA (Groups B and D) had significantly higher response to treatment (P = .001) than patients receiving standard treatment alone (Groups A and C). The adjusted odds ratio (OR) for response to treatment in the epidural group versus the medical group was 5.17 (95% confidence interval [CI]: 1.75-15.23) in the acute group and 5.37 (95% CI: 1.62-17.79) in the chronic groups. The adjusted OR for complete remission in the epidural group versus the medical group was 3.05 (95% CI: 1.20-7.73) in the acute group and 4.46 (95% CI: 1.20-16.54) in the chronic group.CEA can effectively relieve pain caused by PHN and acute HZ and increase remission rates. Combining CEA with standard medical treatment may offer a clinical advantage in the management of pain caused by PHN as well as acute HZ.

Immunogenicity and Safety of the HZ/su Adjuvanted Herpes Zoster Subunit Vaccine in Adults Previously Vaccinated With a Live Attenuated Herpes Zoster Vaccine

Background

Protection against herpes zoster (HZ) induced by the live attenuated zoster vaccine Zostavax (ZVL) wanes within 3–7 years. Revaccination may renew protection. We assessed whether (re)vaccination with the adjuvanted HZ subunit vaccine candidate (HZ/su) induced comparable immune responses in previous ZVL recipients and ZVL-naive individuals (HZ-NonVac).

Methods

In an open-label, multicenter study, adults ≥65 years of age, vaccinated with ZVL ≥5 years previously (HZ-PreVac), were matched to ZVL-naive adults (HZ-NonVac). Participants received 2 doses of HZ/su 2 months apart. The primary objective of noninferiority of the humoral immune response 1 month post–dose 2 was considered demonstrated if the upper limit of the 95% confidence interval (CI) of the adjusted anti–glycoprotein E geometric mean concentration (GMC) ratio of HZ-NonVac over HZ-PreVac was <1.5. HZ/su cellular immunogenicity, reactogenicity, and safety were also assessed.

Results

In 430 participants, humoral immune response to HZ/su was noninferior in HZ-PreVac compared with HZ-NonVac (adjusted GMC ratio, 1.04 [95% CI, .92–1.17]). Cellular immunogenicity, reactogenicity, and safety appeared to be comparable between groups. HZ/su was well-tolerated, with no safety concerns raised within 1 month post–dose 2.

Conclusions

HZ/su induces a strong immune response irrespective of prior vaccination with ZVL, and may be an attractive option to revaccinate prior ZVL recipients.

Clinical Trials Registration

NCT02581410.

Efficacy of the Herpes Zoster Subunit Vaccine in Adults 70 Years of Age or Older

BACKGROUND

A trial involving adults 50 years of age or older (ZOE-50) showed that the herpes zoster subunit vaccine (HZ/su) containing recombinant varicella-zoster virus glycoprotein E and the AS01B adjuvant system was associated with a risk of herpes zoster that was 97.2% lower than that associated with placebo. A second trial was performed concurrently at the same sites and examined the safety and efficacy of HZ/su in adults 70 years of age or older (ZOE-70).

METHODS

This randomized, placebo-controlled, phase 3 trial was conducted in 18 countries and involved adults 70 years of age or older. Participants received two doses of HZ/su or placebo (assigned in a 1:1 ratio) administered intramuscularly 2 months apart. Vaccine efficacy against herpes zoster and postherpetic neuralgia was assessed in participants from ZOE-70 and in participants pooled from ZOE-70 and ZOE-50.

RESULTS

In ZOE-70, 13,900 participants who could be evaluated (mean age, 75.6 years) received either HZ/su (6950 participants) or placebo (6950 participants). During a mean follow-up period of 3.7 years, herpes zoster occurred in 23 HZ/su recipients and in 223 placebo recipients (0.9 vs. 9.2 per 1000 person-years). Vaccine efficacy against herpes zoster was 89.8% (95% confidence interval [CI], 84.2 to 93.7; P<0.001) and was similar in participants 70 to 79 years of age (90.0%) and participants 80 years of age or older (89.1%). In pooled analyses of data from participants 70 years of age or older in ZOE-50 and ZOE-70 (16,596 participants), vaccine efficacy against herpes zoster was 91.3% (95% CI, 86.8 to 94.5; P<0.001), and vaccine efficacy against postherpetic neuralgia was 88.8% (95% CI, 68.7 to 97.1; P<0.001). Solicited reports of injection-site and systemic reactions within 7 days after injection were more frequent among HZ/su recipients than among placebo recipients (79.0% vs. 29.5%). Serious adverse events, potential immune-mediated diseases, and deaths occurred with similar frequencies in the two study groups.

CONCLUSIONS

In our trial, HZ/su was found to reduce the risks of herpes zoster and postherpetic neuralgia among adults 70 years of age or older. (Funded by GlaxoSmithKline Biologicals; ZOE-50 and ZOE-70 ClinicalTrials.gov numbers, NCT01165177 and NCT01165229 .).

Treatment of Postherpetic Neuralgia Using Narrow Band Ultraviolet B Radiation (UVB)

Postherpetic neuralgia (PHN) is a common complication of herpes zoster, frequently unresponsive to most available treatment. The disease is especially difficult to manage in elderly people and has a great impact on the quality of life of patients. Narrow band ultraviolet B radiation may play a role in the prevention and treatment of PHN. Present paper describes a case of a 59 year-old female patient, diagnosed with ophthalmic herpes zoster and postherpetic neuralgia, with positive results using narrow UVB.

Stellate ganglion block can relieve symptoms and pain and prevent facial nerve damage

Ramsay hunt syndrome[1] is a varicella zoster virus infection of the geniculate ganglion of the facial nerve. It is typically associated with a red rash and blister (inflamed vesicles or tiny water filled sacks in the skin) in or around the ear and eardrum and sometimes on the roof of the mouth or tongue. Corticosteroid, oral acyclovir, and anticonvulsant are used for treatment of this. In addition to this sympathetic neural blockade via stellate ganglion block is used to prevent facial nerve damage and relieve symptoms. We present a case of Ramsay hunt syndrome in which pain and symptoms are not relieved by oral medication but by daily sittings of stellate ganglion block with local anesthetic and steroid, pain, and other symptoms are relieved, and facial nerve damage is prevented.

Topical and Intranasal Analgesic Therapy in a Woman with Refractory Postherpetic Neuralgia

A patient-specific, stepped approach to topical and intranasal analgesic pharmacotherapy was effective in reducing refractory postherpetic neuralgia (PHN) not responding to the current standard of care for PHN. The use of topical analgesic therapy allowed for higher concentrations of medication locally while reducing the likelihood of systemic side effects common to the drugs used. No adverse effects were noted for either topical or intranasal drug therapy. The patient-specific, stepped approach resulted in clinically significant decreases in pain on visual analog scale (VAS), with the use of intranasal ketamine 10% solution and topical gabapentin 6%, ketoprofen 10%, lidocaine 5%, and ketamine 10% cream.

One-year follow-up of patients with long-lasting post-herpetic neuralgia

BACKGROUND

Recent information on epidemiology and management of post-herpetic neuralgia (PHN), a painful complication of zoster, is scarce.

METHODS

This study was conducted at the Pain Clinic of the Policlinico Tor Vergata, Rome, Italy, on eighty-five immunocompetent patients with a clinical diagnosis of PHN. At enrollment (time 0, T0), the patients were interviewed by physicians to obtain demographic data and information about their zoster clinical history and underwent a blood test for VZV-DNA research. DN4 and SF-12 questionnaires were used to assess the neuropathic nature of pain and the overall health status, respectively. A one-year follow-up was planned for enrolled cases, who were visited at regular intervals of at least 3 months.

RESULTS

At T0 all the patients were at least 6 months from the episode of acute zoster and still presented with intense pain (mean VAS =6.7; mean DN4 = 5.7). Using antivirals within 72 hours from the rash onset was associated to a significant reduction of pain at T0 (p = 0.006 vs untreated patients). Only 2.6% of patients treated with antivirals during acute zoster but 18.6% of the untreated ones presented with neuropathic pain at T12 (p =0.007), even though the two groups were similar at T0. VZV-DNA was found in 5 out of the 50 available blood samples. At the last follow-up visit, PCS and MCS scores of the PHN patients were found to be recovered over those of the historical age-matched healthy controls. Undesirable side effects of analgesic therapies were observed in 15.3 to 28.8% of the patients.

CONCLUSIONS

Patients who six months after acute zoster still have significant neuropathic pain, have a high probability of suffering from chronic pain in the subsequent months/years. The initial antiviral treatment has a significant impact on the pain. Current strategies of analgesic therapy are effective to achieve relief of pain in PHN patients, but they are burdened with heavy and undesirable side effects.

Safety and efficacy of once-daily gastroretentive gabapentin in patients with postherpetic neuralgia aged 75 years and over

Background

Treatment of postherpetic neuralgia (PHN) is more complicated in elderly patients, and multiple daily dosing, complex titration, and high incidences of adverse events can be limiting for many pharmacological treatment options.

Objective

The aim of this study was to determine whether the efficacy and tolerability of once-daily gastroretentive gabapentin (G-GR) is similar between elderly patients (≥75 years) and younger patients (<75 years).

Methods

Data from two phase III, placebo-controlled studies of 1,800 mg G-GR once daily with dinner in patients with PHN were integrated and analyzed by age subgroups (<75 years, n = 527; ≥75 years, n = 192). Efficacy assessments at endpoint (week 10) included baseline-adjusted change in average daily pain (ADP) and average daily sleep interference (SIS) scores, the proportion of responders (≥30 % pain reduction), and the proportion of patients feeling “Much” or “Very Much” improved on the Patient Global Impression of Change (PGIC).

Results

Compared with placebo, patients in both age subgroups treated with G-GR (placebo/G-GR) had greater reductions in mean ADP (≥75: −21.9/−34.2 %, p = 0.0348; <75: −29.9/−38.3 %, p = 0.0079) and SIS (≥75: −1.3/−2.4, p = 0.0017; <75: −1.8/−2.7, p < 0.0001), more patients were responders (≥75: 30.4/52.0 %, p = 0.0025; <75: 45.0/54.7 %, p = 0.0265), and more felt “Much” or “Very Much” improved on the PGIC (≥75: 20.7/35.0 %, p = 0.0272; <75: 33.6/44.9 %, p = 0.0077). The most common (placebo/G-GR) adverse events (AEs) were dizziness (≥75: 3.3/12.0 %; <75: 1.8/10.4 %), nausea (≥75: 1.0/5.4 %; <75: 2.9/4.2 %), and somnolence (≥75: 0/5.0 %; <75: 3.7/4.2 %). For all patients, AEs rapidly decreased to low steady levels after 4–5 weeks of treatment. The incidence of serious AEs was low and they were reported more frequently in the placebo than in the G-GR group.

Conclusions

Therapy with once-daily G-GR was as effective for treating pain associated with PHN in elderly patients as it was in younger patients. G-GR was well tolerated, and the incidence of the most common AEs did not appear to be age related.

Once-daily gastroretentive gabapentin for the management of postherpetic neuralgia: an update for clinicians

Gabapentin was originally developed as an add-on anticonvulsant drug, but has been widely used in the USA for the management of postherpetic neuralgia since its approval for this indication in 2002. Gabapentin has a short elimination half life and limited absorption due to a saturable L-amino acid transport system, which is expressed predominantly in the proximal small intestine. Hence, the original immediate-release gabapentin formulation (gabapentin TID) must usually be taken three times a day for optimal efficacy. Gabapentin TID is also associated with a high incidence of dizziness and somnolence and some patients are unable to tolerate the doses required for maximum pain relief. A once-daily, gastroretentive formulation of gabapentin was recently approved by the US Food and Drug Administration (FDA) for the management of postherpetic neuralgia. This formulation provides gradual release of gabapentin to the optimal site of absorption in the proximal small intestine and reduces the chance of saturating intestinal uptake, thus enabling once-daily dosing of gabapentin. This gradual release and absorption have been demonstrated in pharmacokinetic studies in healthy subjects. The efficacy of once-daily gastroretentive gabapentin for the management of postherpetic neuralgia has been demonstrated in placebo-controlled clinical studies. In addition, data from these studies suggest that the incidence of dizziness and somnolence may be reduced compared with similar studies using gabapentin TID. This article provides an overview of the pharmacokinetics, efficacy, and safety of once-daily gastroretentive gabapentin for the management of postherpetic neuralgia.

Herpes zoster: family history and psychological stress-case-control study

BACKGROUND

Several studies have reported risk factors for herpes zoster (HZ), but their results remain controversial and difficult to compare because of their limitations regarding sampling and design.

OBJECTIVES

This study was aimed to determine risk factors in ambulatory patients aged 50 years or more, by consulting general practitioners (GPs) in France.

STUDY DESIGN

A prospective, national, matched case-control study was conducted. It involved 121 GPs who recruited 250 cases of HZ and 500 controls (matched by age and sex), aged 50 years and older, between April 2009 and September 2010. GP and patient questionnaires explored the following risk factors: family history of HZ, comorbidities, depression, anxiety, negative life events, physical trauma, alcohol and tobacco consumption, level of education, and various protective factors (such as exposure to children). Odds ratios were estimated using conditional logistic regression.

RESULTS

In multivariate adjusted analysis, a family history of HZ (OR 3.69, 95% CI 1.81-7.51), a HAD depressive score≥8 (OR 4.15, 95% CI 1.88-9.16), and a recent negative life event (OR 3.40, 95% CI 1.67-6.93) were all significantly associated with HZ.

CONCLUSIONS

This case-control study conducted in ambulatory patients in general practice reinforced the hypothesis that, in addition to the age-related decline in VZV-specific T-cell-mediated immunity, depression negative life event and familiar history of zoster increase the risk of occurrence of herpes zoster. In people with familiar history, this risk could be prevented by vaccination.

Trigeminal postherpetic neuralgia responsive to treatment with capsaicin 8 % topical patch: a case report

Postherpetic neuralgia has been variably defined but is generally understood to be pain that persists for longer than a few months after an attack of herpes zoster. Pain persists for years in approximately 10 % of those afflicted with acute herpes zoster. The likelihood of postherpetic neuralgia increases with older age, severity of the zoster, trigeminal location, and other factors. Postherpetic neuralgia is a neuropathic pain and treatment usually involves sequential trials of topical and systemic drugs; a variety of other therapies may be considered in refractory cases. A new topical capsaicin 8 % patch has been approved for this indication based on the positive studies in patients with non-trigeminal postherpetic neuralgia. Experience with the use of the capsaicin 8 % patch for trigeminal distribution neuralgia is lacking. We report a case of trigeminal postherpetic neuralgia which was safely and effectively treated with capsaicin 8 % patch.

Once-daily gastroretentive gabapentin for treatment of postherpetic neuralgia

SUMMARY The immediate-release formulation of gabapentin (gabapentin three-times daily) is approved for treatment of postherpetic neuralgia (PHN). Although it has a low propensity for drug–drug interactions, it requires multiple daily dosing and is associated with a high frequency of dizziness and somnolence. A once-daily formulation of gabapentin was recently approved for the treatment of PHN. This formulation employs a gastroretentive technology to provide a prolonged release of gabapentin. Clinical studies have confirmed the efficacy of once-daily, gastroretentive gabapentin in the treatment of PHN. In addition, these studies have suggested that the rate of dizziness and somnolence may be reduced compared with similar studies using gabapentin three-times daily. This article reviews key aspects of the pharmacology, efficacy and safety of once-daily gabapentin in the treatment of PHN.

Risk of herpes zoster in patients prescribed inhaled corticosteroids: a cohort study

BACKGROUND

Little is known concerning risk factors for herpes zoster in the general population. We hypothesised that inhaled corticosteroids (ICS) are a risk factor for herpes zoster especially among users of inhibitors of cytochrome P450 enzymes involved in their metabolism.

METHODS

We identified a cohort of adult users of respiratory medications in the General Practice Research Database and carried out a nested case control analysis of inhaled corticosteroid use among 8900 new cases of herpes zoster and 88032 controls matching on age and calendar time.

RESULTS

The adjusted odds ratio for the relationship between current use of ICS and the occurrence of herpes zoster was 1.00 (95% confidence interval (CI), 0.94-1.07). There was no increase in risk of herpes zoster even at higher ICS doses; odds ratio 1.05 (95% CI, 0.96-1.14). Among subjects with concomitant prescriptions for an ICS and an inhibitor of cytochrome P450 3A4, the point estimate for the association between herpes zoster and the use of higher doses of inhaled corticosteroids was 1.23 (95% CI, 0.81-1.88).

CONCLUSIONS

The use of inhaled corticosteroids, even at high doses and in conjunction with inhibitors of their metabolism, was not a significant risk factor for the occurrence of herpes zoster in adults.

Economic evaluation of a vaccine for the prevention of herpes zoster and post-herpetic neuralgia in older adults in Switzerland

BACKGROUND

A life-attenuated vaccine aimed at preventing herpes zoster (HZ) and its main complication, post-herpetic neuralgia (PHN), will soon be available in Europe. The study's objective was to assess the clinical and economic impact of a vaccination program for adults aged 70-79 years in Switzerland.

RESULTS

A vaccination strategy compared to a no-vaccination resulted in lifetime incremental cost-effectiveness ratios (ICERs) of 25,538 CHF (23,646 USD) per QALY gained, 6,625 CHF (6,134 USD) per HZ case avoided, and 15,487 CHF (14,340 USD) per PHN3 case avoided under the third-party payer perspective. Sensitivity analyses showed that the model was most sensitive to the discount rates, HZ epidemiological data and vaccine price used.

METHODS

A Markov model, simulating the natural history of HZ and PHN and the lifetime effects of vaccination, previously developed for the UK was adapted to the Swiss context. The model includes several health states including good health, HZ, PHN, and death. HZ and PHN states reflected pain severity.

CONCLUSION

The model predicts clinical and economic benefits of vaccination in the form of fewer HZ and PHN cases and reductions in healthcare resource use. ICERs were within the commonly accepted thresholds in Switzerland, indicating that a HZ vaccination program would be considered a cost-effective strategy in the Swiss setting.

Dementia following herpes zoster encephalitis

We studied the rare case of an older adult with dementia following herpes zoster encephalitis (HZE). This 71-year-old woman presented to us approximately 1 year following resolution of a rapid-onset episode of HZE, and subsequently underwent neuropsychological and neuroimaging examinations. Cognitive assessment revealed impairments in general cognitive functioning, verbal and nonverbal memory, executive functions, speed of information processing, attention/working memory, and motor skills. The patient's neuroimaging data, when compared to a demographically similar healthy control sample (n = 9), demonstrated moderate central and perisylvian brain volume loss, several subcortical lesions in the white matter, and resting state whole brain and hippocampal hypoperfusion. These findings highlight neuropsychological changes evident in a dementia syndrome of this type, and they suggest that early identification and treatment of HZE has implications for the preservation of long-term cognitive functioning.

A health economic model for evaluating a vaccine for the prevention of herpes zoster and post-herpetic neuralgia in the UK

Background

A live-attenuated vaccine aimed at preventing herpes zoster (HZ) and its main complication, post-herpetic neuralgia (PHN) is available in Europe for immunocompetent adults aged 50 years and more. The study objective is to assess the cost effectiveness of a vaccination program for this population in the UK.

Methods

A state-transition Markov model has been developed to simulate the natural history of HZ and PHN and to estimate the lifetime effects of vaccination in the UK. Several health states are defined including good health, HZ, PHN, and death. HZ and PHN health states are further divided to reflect pain severity.

Results

The model predicts that a vaccination strategy for those aged over 50 years would lead to an incremental cost-effectiveness ratio of £13,077 per QALY gained from the NHS perspective, when compared to the current strategy of no vaccination. Age-group analyses show that the lowest ICERs (£10,984 and £10,275 for NHS) are observed when vaccinating people between 60-64 and 65-69 years of age. Sensitivity analyses showed that results are sensitive to the duration of vaccine protection, discount rate, utility decrements and pain severity split used.

Conclusions

Using the commonly accepted threshold of £30,000 per QALY gained in the UK, most scenarios of vaccination programmes preventing HZ and PHN, including the potential use of a repeat dose, may be considered cost-effective by the NHS, especially within the 60 to 69 age-groups.

Health economic evaluation of a vaccine for the prevention of herpes zoster (shingles) and post-herpetic neuralgia in adults in Belgium

OBJECTIVE

To determine the cost-effectiveness of vaccination against herpes zoster (HZ) and post-herpetic neuralgia (PHN) in individuals aged 60 years and older in Belgium.

METHODS

A Markov model was developed to compare the cost-effectiveness of vaccination with that of a policy of no vaccination. The model estimated the lifetime incidence and consequences of HZ and PHN using inputs derived from Belgian data, literature sources, and expert opinion. Cost-effectiveness was measured by the incremental cost-effectiveness ratio (ICER), expressed as cost per quality-adjusted life-year (QALY) gained.

RESULTS

Vaccination in individuals aged 60 years and older resulted in ICERs of €6,799 (third party payer perspective), €7,168 (healthcare perspective), and €7,137 (societal perspective). The number needed to vaccinate to prevent one case was 12 for HZ, and 35 or 36 for PHN depending on the definition used. Univariate sensitivity analyses produced ICERs of €4,959-19,052/QALY; duration of vaccine efficacy had the greatest impact on cost-effectiveness. Probabilistic sensitivity analysis showed at least a 94% probability of ICERs remaining below the unofficial €30,000 threshold.

DISCUSSION

Key strengths of the model are the combination of efficacy data from a pivotal clinical trial with country-specific epidemiological data and complete sensitivity analysis performed. Main limitations are the use of non country-specific PHN proportion and non Belgian disease-specific utilities. Results are comparable with those recently published.

CONCLUSIONS

HZ vaccination in individuals aged 60 years and older would represent a cost-effective strategy in Belgium.

Immunosenescence Modulation by Vaccination

A decline in immune function is a hallmark of aging that leads to complicated illness from a variety of infectious diseases, cancer and other immune-mediated disorders, and may limit the ability to appropriately respond to vaccination. How vaccines might alter the senescent immune response and what are the immune correlates of protection will be addressed from the perspective of 1) stimulating a previously primed response as in the case of vaccines for seasonal influenza and herpes zoster, 2) priming the response to novel antigens such as pandemic influenza or other viruses, 3) vaccination against bacterial pathogens such as pneumococcus, and 4) altering the immune response to an endogenous protein as in the case of a vaccine against Alzheimer’s disease. In spite of the often limited efficacy of vaccines for older adults, influenza vaccination remains the only cost-saving medical intervention in this population. Thus, considerable opportunity exists to improve current vaccines and develop new vaccines as a preventive approach to a variety of diseases in older adults. Strategies for selecting appropriate immunologic targets for new vaccine development and evaluating how vaccines may alter the senescent immune response in terms of potential benefits and risks in the preclinical and clinical trial phases of vaccine development will be discussed.

Comorbidities in a cancer patient: problems in pain management and palliation

Pain management and palliation face a great challenge with inclusion of the palliation teams from the earliest phases of diagnosis. The presented case report highlights that early inclusion of pain and palliative physicians in patient care demands comprehensive evaluation of the symptoms by the palliative physicians with possibly curable comorbid conditions requiring active and aggressive curative management. In summary, it is crucial for the treating palliative physician to be more proactive in the management of comorbid treatable conditions in a patient who may be an established case of advanced stage cancer.

The epidemiological, clinical, and pathological rationale for the herpes zoster vaccine

Worldwide, herpes zoster (HZ) affects millions of patients (particularly older adults) annually and causes significant suffering due to acute and chronic pain, or postherpetic neuralgia (PHN). The objective of this article is to explain the rationale for the HZ vaccine by summarizing data on the epidemiology of HZ in the immunocompetent host, with a focus on recent incidence and risk factor studies; to review information on the burden of HZ; and to discuss the challenges of lessening the morbidity of the disease. The incidence and severity of HZ and PHN are highest in older adults. Given the central nervous system damage caused by HZ, the difficulty of adequately treating HZ to prevent PHN, and the intractability of PHN, the advent of the HZ vaccine appears to be a crucial innovation for preventing HZ and PHN.

Epidemiology and cost of herpes zoster and post-herpetic neuralgia in the United Kingdom

Recent information on epidemiology and management of herpes zoster (HZ) and post-herpetic neuralgia (PHN), a painful complication of HZ, is scarce. The objective of this study was to document the burden of HZ and PHN in the United Kingdom. This retrospective analysis of the UK General Practice Research Database aimed to estimate HZ incidence and proportion of HZ patients developing PHN and to assess management costs in immunocompetent individuals aged ⩾50 years. A cohort of 27 225 HZ patients was selected, corresponding to an incidence of 5·23/1000 person-years. Respectively 19·5% and 13·7% of patients developed PHN at least 1 and 3 months after HZ diagnosis. Mean direct cost was £103 per HZ patient and £341 and £397 per PHN episode (1- and 3-month definition respectively). Both HZ and PHN costs increased markedly with pain severity. This study confirms that HZ and PHN are frequent and costly diseases in the United Kingdom.

An update on the treatment of postherpetic neuralgia

Like other types of neuropathic pain, postherpetic neuralgia (PHN) can be resistant to many types of pharmacologic and interventional therapies. Although many analgesic agents have been used for the treatment of other types of neuropathic pain, tricyclic antidepressants, antiepileptic drugs, opioids, and lidocaine patch appear to demonstrate relative analgesic efficacy for the treatment of pain from PHN. There are fewer studies on the use of interventional options for the treatment of pain from PHN. The majority of interventional therapies show equivocal analgesic efficacy although some data indicate that intrathecal methylprednisolone may be effective. Further randomized, controlled trials will be needed to confirm the analgesic efficacy of analgesic and interventional therapies to determine their role in the overall treatment of patients with PHN.

PERSPECTIVE

This article reviews the analgesic options for the treatment of PHN and suggests that tricyclic antidepressants, membrane stabilizers, opioids, and lidocaine patch may demonstrate analgesic efficacy in this group of patients. These data may potentially help clinicians who attempt to provide analgesia in patients with PHN.

Postherpetic neuralgia: epidemiology, pathophysiology and management

Postherpetic neuralgia (PHN) is a neuropathic pain syndrome and is the most common complication of herpes zoster (HZ; shingles). PHN occurs mainly in HZ patients 60 years of age and older, in particular in those suffering from more severe acute pain and rash. Administration of antiviral drugs reduces the duration of pain associated with HZ. The pathophysiology of PHN may be distinctly different between patients with either reduced or increased skin sensitivity. Therapy is with tricyclic drugs (e.g., nortriptyline), alpha 2 delta-ligands (e.g., gabapentin) or opiates with adjunctive topical lidocaine or capsaicin. Mechanism-based therapy is a desirable goal but so far proves elusive. The incidence of HZ, and therefore that of PHN, is likely to increase as a result of greater longevity and increasing numbers of patients receiving treatment that compromises cell-mediated immunity. A zoster vaccine for administration to adults reduces the incidence of HZ and PHN, as well as the burden of illness associated with these conditions.

A population-based study of the incidence and complication rates of herpes zoster before zoster vaccine introduction

OBJECTIVE

To establish accurate, up-to-date, baseline epidemiological data for herpes zoster (HZ) before the introduction of the recently licensed HZ vaccine.

METHODS

Using data from January 1, 1996, to October 15, 2005, we conducted a population-based study of adult residents (Greater than or equal to 22 years) of Olmsted County, MN, to determine (by medical record review) the incidence of HZ and the rate of HZ-related complications. Incidence rates were determined by age and sex and adjusted to the US population.

RESULTS

A total of 1669 adult residents with a confirmed diagnosis of HZ were identified between January 1, 1996, and December 31, 2001. Most (92%) of these patients were immunocompetent and 60% were women. When adjusted to the US adult population, the incidence of HZ was 3.6 per 1000 person-years (95% confidence interval, 3.4-3.7), with a temporal increase from 3.2 to 4.1 per 1000 person-years from 1996 to 2001. The incidence of HZ and the rate of HZ-associated complications increased with age, with 68% of cases occurring in those aged 50 years and older. Postherpetic neuralgia occurred in 18% of adult patients with HZ and in 33% of those aged 79 years and older. Overall, 10% of all patients with HZ experienced 1 or more nonpain complications.

CONCLUSIONS

Our population-based data suggest that HZ primarily affects immunocompetent adults older than 50 years; 1 in 4 experiences some type of HZ-related complication.

Herpes zoster and postherpetic neuralgia in older adults

Herpes zoster (HZ) afflicts millions of older adults annually and causes significant suffering from acute and chronic pain, or postherpetic neuralgia (PHN). HZ is caused by the reactivation of varicella-zoster virus (VZV) in sensory ganglia in the setting of age, disease, and drug-related decline in cellular immunity. VZV-induced neuronal destruction and inflammation cause the pain, interference with activities of daily living, and reduced quality of life. The optimal treatment of HZ requires early antiviral therapy and pain management. For PHN, evidence-based pharmacotherapy can reduce pain burden. The zoster vaccine is effective in reducing pain burden and preventing HZ and PHN in older adults.

Pregabalin: an antiepileptic agent useful for neuropathic pain

PURPOSE

The pharmacology, pharmacokinetics, clinical efficacy, adverse effects, and dosage and administration of pregabalin are reviewed.

SUMMARY

Pregabalin is the first drug to receive approved labeling from the Food and Drug Administration (FDA) for the treatment of painful diabetic neuropathy and postherpetic neuralgia and is the first antiepileptic agent to receive FDA-approved labeling since 1999. Pregabalin is the pharmacologically active S-enantiomer of racemic 3-isobutyl gamma-aminobutyric acid. Pregabalin has demonstrated efficacy in the management of neuropathic pain associated with diabetic peripheral neuropathy, postherpetic neuralgia, and as adjunctive therapy for adult patients with partial onset seizures. Its exact mechanism of action is unknown. Pregabalin is rapidly absorbed and exhibits linear pharmacokinetics after oral administration. The lack of hepatic metabolism and lack of interaction with cytochrome P-450 isoenzymes explain the absence of drug interactions with pregabalin. Several clinical studies have demonstrated pregabalin's efficacy for each of the FDA-approved indications, with dizziness and somnolence reported as the most common adverse events. Pregabalin has been designated as a Schedule V controlled substance because of its potential for abuse and dependence. The starting dosage for patients with neuropathic pain associated with diabetic peripheral neuropathy is 50 mg three times daily and may be increased to 300 mg daily within one week based on efficacy and tolerability. The starting dosage for patients with partial-onset seizures is 75 mg twice daily or 50 mg three times daily and may be increased to 600 mg daily based on individual response and tolerability.

CONCLUSION

Pregabalin may be beneficial for the treatment of neuropathic pain or partial-onset seizures in patients who do not respond to conventional treatments or cannot tolerate their adverse effects.

Chickenpox, chickenpox vaccination, and shingles

Chickenpox in the United Kingdom, where vaccination is not undertaken, has had a stable epidemiology for decades and is a routine childhood illness. Because of vaccination, chickenpox is now a rarity in the USA. In the UK vaccination is not done because introduction of a routine childhood vaccination might drive up the age at which those who are non-immune get the illness (chickenpox tends to be more severe the older you are), and the incidence of shingles may increase. The United Kingdom is waiting to see what happens in countries where vaccination is routine.

Managing pain after shingles: a nursing perspective

Post-herpetic neuralgia (PHN) is the neuropathic pain syndrome that may develop following an attack of shingles. While for many the symptoms subside, there can be long-term pain problems for up to 40% of those affected with PHN, and for 3% of these, symptoms can be severe (Dworkin and Portenoy, 1996). Knowledge and understanding of the symptoms and various treatments and approaches available is important to enable nurses and patients to work together in partnership to achieve the best outcomes. Realizing that more than one approach may be needed can allow for treatments which are complementary and for optimization of both biomedical and self-care approaches.

Tolerability of treatments for postherpetic neuralgia

Herpes zoster occurs in up to 20% of people infected with varicella-zoster virus, due to reactivation of the virus from latently infected sensory ganglia. Although pain is a typical feature of acute zoster, pain persisting for more than a month after resolution of the rash is less common and is termed postherpetic neuralgia (PHN). The pain associated with PHN is neuropathic in origin and is notoriously difficult to treat. The incidence of herpes zoster and its associated complications both increase with age, so PHN should be seen more commonly in an aging population. Vaccination with live, attenuated varicella vaccine is safe and efficacious, particularly in children. It decreases the incidence of acute varicella and subsequent herpes zoster. Aciclovir is well tolerated, with renal toxicity only at high intravenous doses. Treatment of acute varicella with aciclovir attenuates acute illness but does not prevent herpes zoster. Treatment of herpes zoster with aciclovir or its derivatives minimises symptoms and may reduce the rate of PHN. Foscarnet is an alternative for an aciclovir-resistant virus but its use is limited by renal and CNS toxicity. Corticosteroids reduce acute pain in herpes zoster but do not affect the incidence of PHN. Their use in some patients may be limited by adverse effects such as gastritis and impaired glucose tolerance. Treatment of established PHN is difficult and may require a holistic approach. Tricyclic antidepressants and gabapentin are the systemic agents with the most proven benefit, although opioids such as oxycodone and NMDA receptor antagonists such as ketamine may be useful in some people. Adverse effects from tricyclic antidepressants are common but usually mild, while gabapentin is generally well tolerated. Although effective, the relatively common adverse effects of opioids and ketamine limit their usefulness in treating PHN. Topical treatment with 5% lidocaine patch or capsaicin is of benefit in some patients and is generally well tolerated. Intrathecal methyl prednisolone may be considered for intractable pain but efficacy and safety have not been confirmed.

Repetitive paravertebral nerve block using a catheter technique for pain relief in post-herpetic neuralgia

We described in this report a case of post-herpetic neuralgia refractory to medical therapy that was successfully treated with repetitive injections of local aesthetic mixture (bupivacaine 0.5% 19 ml and clonidine 150 microg ml(-1) 1 ml) every 48 h for 3 weeks using a paravertebral catheter inserted at T2-T3 level.

Analgesic therapy in postherpetic neuralgia: a quantitative systematic review

BACKGROUND

Postherpetic neuralgia (PHN) is a complication of acute herpes zoster, which is emerging as a preferred clinical trial model for chronic neuropathic pain. Although there are published meta-analyses of analgesic therapy in PHN, and neuropathic pain in general, the evidence base has been substantially enhanced by the recent publication of several major trials. Therefore, we have conducted a systematic review and meta-analysis for both efficacy and adverse events of analgesic therapy for PHN.

METHODS AND FINDINGS

We systematically searched databases (MEDLINE 1966-2004, EMBASE 1988-2004, CINAHL 1982-2002, and PubMed [29 October 2004]) for trials of PHN. We also searched references of retrieved studies and review articles for further trials. We included trials that examined adult patients with PHN of greater duration than 3 mo, that were blinded, randomised, and had at least one measure of pain outcome. Dichotomous pain outcome data were extracted for 50% decrease in baseline pain using a hierarchy of pain/pain-relief measurement tools. Where available, dichotomous data were also collected for adverse events. Calculated estimates of efficacy included relative benefit and number needed to treat. Of 62 studies identified, 35 were randomised controlled trials. Of these, 31 were placebo controlled and suitable for meta-analysis, from which it was possible to extract dichotomous efficacy outcome data from 25. This meta-analysis revealed that there is evidence to support the use of the following orally administered therapies: tricyclic antidepressants, "strong" opioids, gabapentin, tramadol, and pregabalin. Topical therapies associated with efficacy were lidocaine 5% patch and capsaicin. Finally, a single study of spinal intrathecal administration of lidocaine and methyl prednisolone demonstrated efficacy, although this has yet to be replicated. Data suggest that the following therapies are not associated with efficacy in PHN: certain NMDA receptor antagonists (e.g., oral memantine, oral dextromethorphan, intravenous ketamine), codeine, ibuprofen, lorazepam, certain 5HT1 receptor agonists, and acyclovir. Topical administration of benzydamine, diclofenac/diethyl ether, and vincristine (iontophoresis) are similarly not associated with efficacy, nor are intrathecal administration of lidocaine alone or epidural administration of lidocaine and methylprednisolone, intravenous therapy with lidocaine, subcutaneous injection of Cronassial, or acupuncture. However, many of the trials that demonstrated a lack of efficacy represented comparatively low numbers of patient episodes or were single-dose studies, so it may be appropriate to regard such interventions as "not yet adequately tested" rather than demonstrating "no evidence of efficacy." Topical aspirin/diethyl ether has not been adequately tested.

CONCLUSION

The evidence base supports the oral use of tricyclic antidepressants, certain opioids, and gabapentinoids in PHN. Topical therapy with lidocaine patches and capsaicin is similarly supported. Intrathecal administration of methylprednisolone appears to be associated with high efficacy, but its safety requires further evaluation.